| Back River | |
| Pushpin Map: | Massachusetts#USA |
| Pushpin Map Size: | 250 px |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | States |
| Subdivision Name2: | New Hampshire, Massachusetts |
| Subdivision Type3: | Counties |
| Subdivision Name3: | Rockingham, NH, Essex, MA |
| Subdivision Type4: | Towns |
| Subdivision Name4: | Kensington, NH, South Hampton, NH, Amesbury, MA |
| Length: | 6.5miles |
| Source1 Location: | Kensington, Rockingham County, New Hampshire |
| Source1 Coordinates: | 42.9072°N -70.9658°W |
| Source1 Elevation: | 150feet |
| Mouth: | Powwow River |
| Mouth Location: | Amesbury, Essex County, Massachusetts |
| Mouth Coordinates: | 42.8556°N -70.9272°W |
| Mouth Elevation: | 0feet |
| Tributaries Left: | Lucy Brook |
The Back River is a 6.5adj=midNaNadj=mid river located in New Hampshire and Massachusetts in the United States. It is a tributary to the Powwow River, part of the Merrimack River watershed. Approximately of the river are in New Hampshire,[1] with the remaining in Massachusetts.
Prior to European settlement in the early 17th century, Native Americans of the Pennacook tribe lived in the area, and used both the Back River and parent Powwow River for transportation and fishing. The native population was essentially destroyed by the 1617-19 epidemic in the area.[2]
In the 1950s, the Clarks Pond Dam was built in Amesbury, Massachusetts, creating the pond of that name. Since the pond's creation, it has been degraded by residential building in the area, and was considered "threatened" in a 2013 report, by residential run-off and silt deposits.[3]
The Back River rises in Kensington, New Hampshire, and flows southeast, almost immediately entering the town of South Hampton. The river turns south and enters Massachusetts in Amesbury, joining the Powwow River at tidewater just downstream from the city's center at the falls of the Powwow.